Clostridium difficile, which is considered to be the major causative agent of antibiotic-associated colitis in humans, produces at least two toxins. Several attempts have been made to develop a method which can detect one or both toxins and is sensitive, specific, and easy to perform. We have evaluated 304 stool specimens submitted for C. difficile toxin assay by both a conventional tissue culture cytotoxicity assay and by a latex agglutination test. Of the 304 specimens submitted, 26 were positive for toxin by cytotoxicity assay. Fifteen of these 26 positive specimens were also positive by latex agglutination. Four specimens were positive by latex agglutination and negative by cytotoxicity assay. The sensitivity and specificity of latex agglutination was 63% and 98%, respectively, as compared to the conventional method. The latex procedure is simple and specific, but not sufficiently sensitive, for the detection of c. difficile toxin in clinical specimens.